Acquisitions (Details 3) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Aug. 31, 2017	Feb. 01, 2017	Oct. 01, 2016	Mar. 01, 2016
Business Acquisition [Line Items]
Contingent consideration	$ 4,225,000	$ 4,225,000	$ 5,258,000
Business acquisition contingent consideration, other long term liability	1,500,000	1,500,000	1,700,000
Contingent Consideration Payments		4,657,000	2,244,000	$ 2,284,000
Contingent Consideration Liability, Payments		5,065,000
Original range of potential undiscounted payments maximum	20,130,000	20,130,000
Maximum contingent consideration due in 2015	12,130,000	12,130,000
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Year Two	4,000,000	4,000,000
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Thereafter	4,000,000	4,000,000
Maverick Solutions [Member]
Business Acquisition [Line Items]
Contingent consideration	1,979,000	1,979,000	5,258,000
Contingent Consideration Payments	4,100,000
Contingent Consideration Liability, Payments		4,098,000
Original range of potential undiscounted payments maximum	5,902,000	5,902,000
Maximum contingent consideration due in 2015	5,902,000	5,902,000
Maximum contingent consideration due in Total							$ 10,000,000
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Year Two	0	0
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Thereafter	0	0
Maverick Solutions [Member] | Minimum [Member]
Business Acquisition [Line Items]
Original range of potential undiscounted payments	0	0
Maverick Solutions [Member] | Maximum [Member]
Business Acquisition [Line Items]
Original range of potential undiscounted payments	10,000,000	10,000,000
McKinney Rogers [Member]
Business Acquisition [Line Items]
Contingent consideration	1,501,000	1,501,000	0
Contingent Consideration Liability, Payments		967,000
Original range of potential undiscounted payments maximum	12,000,000	12,000,000				$ 18,000,000
Maximum contingent consideration due in 2015	4,000,000	4,000,000
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Year Two	4,000,000	4,000,000
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Thereafter	4,000,000	4,000,000
McKinney Rogers [Member] | Minimum [Member]
Business Acquisition [Line Items]
Original range of potential undiscounted payments	0	0
McKinney Rogers [Member] | Maximum [Member]
Business Acquisition [Line Items]
Original range of potential undiscounted payments	18,000,000	18,000,000
CLS [Member] [Member]
Business Acquisition [Line Items]
Contingent consideration	669,000	669,000	$ 0
Contingent Consideration Liability, Payments		0
Original range of potential undiscounted payments maximum	2,228,000	2,228,000			$ 2,200,000
Maximum contingent consideration due in 2015	2,228,000	2,228,000
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Year Two	0	0
Business Combination, Contingent Consideration Arrangements, Range Of Outcomes, Value, High, Thereafter	0	0
CLS [Member] [Member] | Minimum [Member]
Business Acquisition [Line Items]
Original range of potential undiscounted payments	0	0
CLS [Member] [Member] | Maximum [Member]
Business Acquisition [Line Items]
Original range of potential undiscounted payments	$ 2,228,000	$ 2,228,000
Jencal Training [Member]
Business Acquisition [Line Items]
Maximum contingent consideration due in Total								$ 200,000